Ventilated rib for gun barrels and method of installation

ABSTRACT

A VENTILATED RIB FOR GUN BARRELS AND METHOD OF INSTALLATION ARE PRESENTED WHEREIN THE RIB IS FIXED TO THE GUN BARREL BY A SUITABLE MASTIC MATERIAL. THE RIB IS PERFERABLE ALUMINUM TO PROVIDE THE NECESSARY HEAT CONDUCTIVITY CHARACTERISTICS, AND A SUBSTANTIALLY WARP-FREE RIB MOUNTING IS ACCOMPLISHED THROUGH THE PARTICULAR STEPS OF THE INSTALLATION PROCESS WHEREIN THE RIB IS HELD IN A RETAINING FIXTURE WHILE BEING BONDED TO THE GUN BARREL.

1971 A. Y. GRAHN 3,556,889

VENTILATED RIB FDR GUN BARRELS AND METHOD OF INSTALLATION Filed Jan. 24, 1969 2 Sheets-Shed 1 w ,&N II [I 1 Q Jj R @Q w w M w A M F! Q Y w mhk w x& V\ Qw d N QR Jan. 19, 1971 A. Y. GRAHN VENTILATED RIB FOR GUN BARRELS AND METHOD OF INSTALLATION 2 Sheets-Sheet 2 Filed Jan. 24, 1969 FPO/V 0766 7 HOZKfl United States Patent 3,556,889 VENTILATED RIB FOR GUN BARRELS AND METHOD OF INSTALLATION Arne Y. Grahn, Granby, Conn., assignor to The Poly- Choke Company, Incorporated, East Hartford, Conn.,

a corporation of Connecticut Filed Jan. 24, 1969, Ser. No. 793,762 Int. Cl. B23p 13/00; F41c 1/00, 21/00 U.S. Cl. 156-91 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to sighting ribs for gun barrels. More particularly, this invention relates to ventilated sighting ribs for gun barrels and to the method of installation of ventilated ribs on gun barrels.

(2) Description of the prior art Ventilated sighting ribs for gun barrels are known in the art and are usually contemplated for use with shotguns. The ribs are employed as a heat transfer device to dissipate the heat generated through firing, especially repeated and rapid firing, of the gun. Unless means are provided to dissipate this heat, the heat waves radiating from the gun may constitute a visible interference with the shooters sight and thus interfere with proper aiming. Accordingly, it has been suggested in the past to employ ventilated sighting ribs, the ventilation feature contributing to increase heat dissipation. An example of one such ventilated rib structure may be seen in U.S. Pat. No. 3,016,- 613. However, persistent problems have been encountered in the art both in providing a straight, i.e., warp-free, rib, in avoiding damage to the gun barrel during installation, and in preventing separation of the rib from the gun barrel during operation. These problems have developed, at least in part, from the fact that the rib is ordinarily constructed of a lightweight high heat conductivity material such as aluminum which is susceptible to warpage and which is difficult to secure to the gun barrel because of the difference in metals between the rib and the gun barrel. Previous attempts to adequately secure the rib to the gun barrel have included various types of fusion processes and mechanical installations such as studs or other fastening means extending between the rib and the gun barrel. However, these previous approaches have been unsatisfactory for several reasons. These previous approaches present a significant potential for serious damage to the gun barrel since welding may warp the gun barrel or a mechanical fastener may penetrate the barrel; and these approaches have not eliminated warpage of the rib, either in a horizontal direction or in a vertical direction. A significant shortcoming of the prior approaches has been that a mistake ruins the gun barrel; resistance welding puts dimples in the barrel; soldering distorts the barrel; and stud mounting by impact work hardens the barrel.

SUMMARY OF THE INVENTION In the present invention a ventilated n'b, preferably an aluminum rib, is secured to a steel gun barrel by a mastic ice material, such as a polysulfide sealer, which remains elastic after sealing. The rib is held in a straightening fixture during the bonding operation so that the rib is warp free when secured to the barrel. The mastic, either alone or together with a mechanical hold down at the muzzle end and possibly a mechanical hold down at the receiver end, firmly secures the warp-free rib to the barrel, and repeated rapid-rate firing does not produce any subsequent warpage of the rib. The straightening fixture whereby the rib is assured to be substantially warp free at the time of installation is a significant feature in the overall success of the present invention as is also the use of a suitable mastic. Ribs installed in accordance with the present invention are substantially warp free and do not become warped during operation; and the present invention eliminates damage to the rifle barrel during installation which might otherwise result from fusing the rib to the barrel by welding or soldering or such as might result from work hardening or penetration of the barrel for a mechanical mounting. Secondary machining of the rib after installation, such as might otherwise be necessary to eliminate warpage or to provide contouring, is unnecessary with this invention.

Accordingly, one object of the present invention is to provide a novel and improved ventilated gun sight rib wherein warpage of the rib is substantially eliminated.

Another object of the present invention is to provide a novel and improved ventilated gun sight rib which can be mounted on the gun barrel without significant danger of damaging the gun barrel.

, Still another object of the present invention is to provide a novel and improved ventilated gun sight rib wherein the rib is secured to the gun barrel by a mastic material.

Still another object of the present invention is to provide a novel and improved method of installing a ventilated gun sight rib on a gun barrel.

Other objects and advantages will be apparent and understood from the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWING In the drawings, wherein like elements are numbered alike in the several figures, FIG. 1 is a side elevation view of a ventilated rib.

FIG. 2 is a side elevation view of a holding fixture employed in the process of the present invention.

FIG. 3 is a view taken along line 33 of FIG. 2 showing a sectional elevation view of the holding fixture of FIG. 2.

FIG. 4 is a partial view showing a ventilated rib mounted on a gun barrel in one stage of operation of the process of the present invention.

FIG. 5 is a partial view showing the muzzle end of a gun barrel during installation of a rib in accordance with the process of the present invention.

. FIG. 6 is a side elevation view showing a rib retained in the holding fixture and aligned for mounting on the gun barrel.

FIG. 7 shows a rib in the holding fixture mounted on a gun barrel.

FIG. 8 is a flow diagram showing the various steps of the process of the present invention.

DESCRIPTION OF THE PREFERRED EMBODI- MENT Referring to FIG. 1, the gun sight rib 10 for use in the present invention is intended to be substantially the same type of gun sight rib as shown in U.S. Design Pat. No. 195,340. The rib may be aluminum, steel or some other suitable metal, but the following discussion will presume the rib to be aluminum.

Rib 10 has elongated openings or slots 12 spaced along a substantial part of the intermediate length of the rib and separated by post elements 14. Openings 12 provide ventilation for the rib, and the posts 14 serve to separate and support the upper and lower segments 16 and 18, respectively, formed by the slots.

Rib is formed from a rectangular piece of bar'stock. In forming the rib, ramp 20 is first milled at one end of a selected length of bar stock. Ramp 20 in FIG. 1 is shown contoured for a recoiling barrel installation, and it will be understood that ramp contouring may vary depending on the gun involved. In the next step of formation, openings 12 and a scallop or fluted upper surface 22 are milled simultaneously. The rib thus formed is then transferred to a tracer miller machine where the bottom surface 24 is traced milled by tracing the contour of the gun barrel on which the rib is to be mounted. Thus, a contour is milled into bottom surface 24 to match the curvature of the gun barrel, and a perfect fit between the rib and the gun barrel is thus assured.

The procedure just described wherein the rib is cut to length and appropriately milled is not shown in the flow diagram of FIG. 8 since, although the steps form part of the total procedure, these steps may properly be considered part of a preliminary operation. It is contemplated that a large number of ribs could be prepared in this preliminary process and then stored for use when desired. The ribs are blackened by a black anodized process any time prior to use. It should be noted that a hot bluing solution cannot be used because of the aluminum rib. Hot black oxide could be used to blacken steel ribs.

In the process of installation, the front sight of the shotgun barrel is removed and, if not already present, a hole 25 (see FIG. 5) is drilled and tapped at the muzzle end of the barrel at the location of the front sight. The removal of the front sight and the drilling and tapping of the hole are depicted as step A in FIG. 8. The rib is then laid on the barrel as shown in FIG. 4 (the barrel and rib being shown broken to indicate length), At this stage the end of the rib should extend over the muzzle of the barrel as shown in FIG. 4, the rib having been properly sized during the initial milling operations to insure this overhang. The gun barrel is indicated at 26, the muzzle at 28 and the receiver at 30 in FIG. 4. Ramp 20 is then aligned with the chamber end of the barrel and with the sighting plane on the receiver, and the rib is taped to the barrel with tape such as glass filament tape 32. The height of the rib with respect to the receiver may then be checked; the top surface 16 of the rib should be slightly above the top of the receiver by from .010 inch to .030 inch. The rib is then removed from the barrel. The positioning, taping and checking of the height of the rib are depicted in FIG. 8 as step B. A hole 34 (see FIG. 5) is then drilled in the front end of the rib corresponding to the location of the sight hole 25, and a hole 36 may also be drilled in the ramp end of the rib. The drilling of the rib hole or holes is depicted as step C in FIG. 8. Referring to FIG. 5, the rib is then remounted on the barrel and secured by means of a screw 38 passing through rib hole 34 to sight hole 25. The alignment of the chamber end is then rechecked and a mark is scribed on the underside of the rib in line with the muzzle of the barrel. Step D in FIG. 8 depicts this remounting, realignment and scribing. The rib is again removed from the barrel, the part overhanging the scrib mark (as depicted in the dotted portion in FIG. 5) is cut off and the end squared, and the ramp end may be trimmed, if necessary. Any parts where bare aluminum is exposed are then blackened with a suitable touch up. The cutting of the rib to remove excess, squaring and touch up are depicted as step E in FIG. 8.

Steps A through E described above are primarily directed to the installation of a rib as a modification of a gun after original manufacture of the gun has been completed, i.e., otherwise than as an original equipment part of the gun manufacturing process. However, the ribs can also be installed as original equipment in the manufacture of the gun, in which case any one or more, or all, of steps A through E can be eliminated by establishing and maintaining proper dimensions and tolerances whereby ribs are produced of proper size and with properly located holes ready for direct installation as original equipment.

In either event, either as a modification installation or as original equipment, the rib is now ready for installation, and it is placed in a holding fixture 40. The details of holding fixture 40 are shown in FIGS. 2 and 3, and rib 10 is shown positioned in holding fixture 40 in FIG. 6.

Referring to FIGS. 2 and 3, holding fixture 40 is an aluminum bar having a plurality of through holes 42 therein spaced along the length of the bar. It will be understood that the bar is shown broken in FIG. 2 merely for the purpose of indicating an extended length, and the length of the bar with respect to the length of the rib can be best seen in FIG. 6. As can be seen in FIG. 3, the through holes 42 extend completely through the holding fixture with a threaded end 43, and cap screws 44 are positioned in each of the through holes. A recess 46 having a horizontal base and vertical side walls is formed along the entire length of fixture 40, and a vertical space or gap 48 also extends along the length of fixture 40 perpendicular to the horizontal base of recess 46. A piece of glass filament tape 50 is positioned in recess 46 against the horizontal base of the recess along the entire length of the fixture. The tape serves to protect recess 46 and gap 48 from becoming clogged with the mastic which is used in bonding the rib to the gun barrel. If the base of recess 46 becomes contaminated with any of the mastic, the tape can be removed and replaced with a clean layer of tape.

When a rib is ready for final installation, the rib is placed in holding fixture 40 with fluted surface 22 set into the bottom of recess 46 so that fluted surface 22 bears against tape 50 and contoured bottom surface 24 of the rib faces outwardly from the holder. Cap screws 44 are then tightened one at a time progressing from one end of the fixture to the other end with the rib being held tightly into the fixture at the location of each cap screw when the particular screw is being tightened. The tightening of the cap screws pulls the sides of the fixture together to firmly grasp the rib. When it is thus mounted in the holding fixture, rib 10 is held flat and straight, and remains flat and straight throughout the rest of the installation operation so that proper final installation of the rib is assured without any warping or wavy appearance of the finally installed rib.

The rib as finally retained in holding fixture 40 in preparation for installation on the gun barrel is shown in FIG. 6, and it will be observed that a part of the rib (preferably at least 1 inch) extends beyond the holding fixture at each end of the fixture. After having been mounted in the holding fixture, the contoured bottom surface 24 of the rib is rubbed with an emery cloth or other abrasive to remove the anodizing on that surface. The step of placing the rib in the holding fixture, tightening the set screws to urge the side walls of the holding fixture inwardly to grasp and retain the rib, and the deanodizing of contoured lower surface 24 are indicated as step F in FIG. 8.

The mastic with which the rib is bonded to the gun barrel is then applied to contoured surface 24. The mastic is a black adhesive, preferably a polysulfide sealer, which remains elastic after setting. Both the top of the gun barrel and surface 24 may be cleaned with a suitable cleaning agent before applying the mastic to surface 24. The step of cleaning the surfaces and applying the mastic to surface 24 is indicated as step G in FIG. 8.

The rib, still mounted in the holding fixture, is then placed on the gun barrel in an approximate correct position and alignment, and the front end of the rib is secured by screw 38 passing through rib hole 34 to sight hole 25 at the muzzle end of the barrel. Pressure, which may be manual pressure, is then applied prOgreSSivelv from the muzzle end to the chamber end to squeeze the rib and barrel together. An even and firm pressure should be applied along the entire length of the fixture. Proper alignment of the ramp end of the rib is then checked and ascertained, and then the fixture and rib are taped to the barrel with glass filament tape 52 as shown in FIG. 7 to secure the rib for retention during curing. FIG. 7 shows the rib and holding fixture mounted on the gun barrel and in proper position for final curing. The placing of the rib and fixture on the gun barrel, the application of the pressure, and the application of the tape are indicated as step H in FIG. 8.

Rib 10 mounted in holding fixture 40 and taped to barrel 26 is then allowed to remain as shown in FIG. 7 for a suflicient period of time to allow curing of the mastic. The curing is indicated as step I in FIG. 8.

After the mastic has been allowed to cure, the glass filament tape 52 and holding fixture 40 are removed whereby rib 10 is now firmly bonded to barrel 26 without any warping or waviness. In order to clean up and remove excess mastic which will have bled out from under the rib, the excess mastic may be swabbed with a cleaning agent and then scrapped off with a wooded dowel having a chisel-like point. The removal of the tape and holding fixture and the cleaning of the excess mastic is indicated as step I in FIG. 8.

In the final steps of installation, fastening screw 38 is removed and replaced with a front sight which is retained by reinserting screw 38 or a substitute which is fastened through rib hole 34 to sight hole 25 to serve as a fastener between the rib and the gun barrel. The step of installing the sight hold down screw is indicated as step K in FIG. 8.

As an optional feature, a mechanical hold down can be provided at the ramp end of the rib by drilling a hole through the ramp and into the barrel and then inserting a hold screw.

The installation of the rib is now completed, and the process produces a rib which is substantially warp free and which will not be disturbed by the high temperatures generated by rapid and repeated firing. Furthermore, the entire installation procedure is carried out without exposing the gun barrel to any hazard which might result in permanent damage.

While a preferred embodiment has been shown and described, various modifications and substitutions may be made without departing from the spirit and scope of the present invention. Accordingly, it is to be understood that this invention has been described by way of illustration and not limitation.

What is claimed is:

1. The method of installing a ventilated rib on a gun barrel including the steps of:

securing the rib in a holding fixture, said rib having an upper surface for sighting and a lower surface to be bonded to a gun barrel, said lower surface being exposed when said rib is in said holding fixture; applying a mastic material to said exposed lower surface of said rib; locating said rib along a gun barrel with said mastic in contact with said barrel; applying pressure along the length of said holding fixture to urge said rib and barrel together; applying retention means to hold said rib and holding fixture on said barrel during curing of said mastic; and removing said retention means and said holding fixture. 2. The method of installing a ventilated rib as in claim 1 including:

sizing said rib to desired dimensions and forming at least one hole therethrough for a mechanical elemerit; and installing at least one mechanical fastening element between said rib and said gun barrel. 3. The method of installing a ventilated rib as in claim 2 wherein:

said one hole is adjacent the muzzle end of said barrel;

' and wherein said step of installing a mechanical fastening element includes mounting a sight element on said rib adjacent the muzzle end of said barrel. 4. The method of installing a ventilated rib as in claim 1 including the steps of:

cleaning said lower surface of said rib prior to applying mastic thereto; and removing excess mastic from the junction between the rib and barrel after curing. 5. The method of installing a ventilated rib as in claim 1 wherein:

said step of applying pressure along the length of said barrel includes applying pressure sequentially from one end of the barrel to the other end. 6. The method of installing a ventilated rib as in claim 1 wherein:

said step of securing the rib in a holding fixture includes tightening said rib in said fixture by urging together walls of said fixture abutting the sides of said rib.

References Cited UNITED STATES PATENTS 2,460,181 1/ 1949 Marshall l5691 2,929,164 3/1960 Browning 42-76 3,107,450 10/ 1963 Snyder et al 4276 3,116,198 12/ 1963 Grawey et a1. 156-91 BENJAMIN A. BORCH ELT, Primary Examiner C. T. JORDAN, Assistant Examiner US. Cl. X.R. 29-1.1; 33-47; 421, 76

Disclaimer 3,556,889.Ame Y. Gmlm, Granby, Conn. VENTILATED RIB FOR GUN BARRELS AND METHOD OF INSTALLATION. Patent dated Jan. 19, 1971. Disclaimer filed Apr. 10, 1972, by the assignee, The Poly-Choke Company, [near orated.

Hereby enters this disclaimer to c aim 2 of said patent.

[Oyficz'al Gazette J uly 11,1972] 

